Laura,
I haven't had any hand/arm shakes but I do get trembly if I start getting nervous, worried or especially startled. I have PTSD from a concussion/brain injury 4 yrs ago.
Anti-anxiety meds are helpful but addictive and I personally would like to find a substitute. If you have a choice, choose something non-addictive. Hell most likely be on it for quite awhile. Topamax helped my headaches but the effects wore off quickly. Currently, a new dr prescribed indomethacin, and I'm having some luck with it. I will be trying Botox injections next month. I need to get off the Vicodin. It's the only thing so far that comes close to handling the pain, but it too doesn't last until the next 8 hr mark. :-( I'm not taking anything for sleep, and it's a drag. I never get a full nights sleep anymore. (4 hrs last night) Hang in there. He's lucky to have you helping him. Most friends and family are and want to be helpful, but quiet and rest was probably the thing I needed most. It made me crazy to sit still and not be allowed to go to work. It was so hard.
Keep researching and reaching out. Don't give up.